Method of coating vessels



' July 22, 1922, and September 21, 1922), of I Patented Apr. 1!?26.

UNITED. STATES.

PATENT OFFICE.

MAX'DB.EIFUSS, or men-Burn, GERMANY.

* METHOD OF COATING VESSELS.

No Drawing. 7

which the following is a specification.

The present invention relates to a method of coating vessels with an alloy which is highly resistant to the destructive action of acids, saltsiand the like, and has particular reference to a method for covering iron vessels on their inside. The alloys hitherto known were either-quite insuflicient and not resistant enough or on the other handthey dyed the substances dissolved, so that cer- I tain salts as for instance chloride of ammonium, could not atall be manufactured in a colorless condition.

The feature of the presentinvention is to coat the interior surfaces only, in the manufacture of vessels or otherarticles, so that such vessels or articles are perfectly immlme from attacks by acids, salts and the like,

, and no discoloration offlsubstances in contact therewith is liable to be produced.

Besides the alloy produced according to the present invention has the property that it can be easily cast and welded together with iron. oThi's property renders the alloy in question especially useful for covering the inside of iron vessels being used injthe chemical manufacture as boilers. 7 As iron is cheaper and has a greater rigidity than the said alloy, it is not necessary to construct such vessels entirely of the alloy used in connection with the present method as a proportionally thin layer of the alloy proper is suflicient for producing vessels of great volume with relatively small weight but ofiering'great resistance against acids and salts. An alloy consisting of copper, aluminum and nickel is preferably used in connection with the invention. a

A suitable and practical alloy contains 1011% Al, 40% Ni, 2-5% Pb, .5% Fe, 81.5-73,% Cu.

Ammonium hydroxide does not destroy such an alloy even at high temperature, which does not occur in any of the alloys hitherto known. Up to now the opinion? thev be repeated. By this manner it-is possible 110 was predominant that by increasing Application filed november 14, 923. Serial m. 674,758.

- amount of nickel in alloys for the present purpose, that is for the evaporation of ammonium chloride, goods results could be obtained, but all tests have shown, that by increasing the amount of nickel over the limits above indicated the chemical resistance against ammonia was diminished.

The alloy is especially suitable for evaporizing the solution of zinc in autoclaves. Besides this the alloy is absolutely resistant to weak sulphate solutions which are nearly saturated, especially to, solutions of sulphate of ammonium. A

The alloy also has the property that it .can very easily be fused or welded to iron, which possibility renders" it possible to cut the interior surfaces of iron vessels, such as are commonly used as boilers in chemical manufactures. Thus considerable economy in.- fmanufacture is produced since iron is cheaper than the alloy and it is possible instead of making such vessels wholly of the ,alloy to makethem mainly of iron which has the-further advantage of producing vessels of greater strength and to form a comparatively little weight which offers great resistance to the destructive action of the acids, salts and the like. I When such an alloy is employed in a liquid state for covering the inside of a boiler or-if plates or rods of this alloy are to'be welded upon iron vessels, an alteration of the alloy by dissolving of iron of the iron vessel takes places. For the purpose of obtaining a quite ure alloy upon the surface of the vessel to be covered sev'- eral layers of such an alloy are combined one after -the other so that finally the whole surface consists of the alloy or bronze P PB The manner of covering iron vessels. by means of the said alloy can be executed in manifold ways. For instance borax is applied to the carefully cleansed surface and i the latter is heated in a'reducing fiame to a to completely coat even and curved surfaces, so that on the surfaces only-the pure alloy remains.

A further method of coating vessels by means of the present alloys consists therein, that the iron vessel is heated from be- 'low into a red hot condition. Afterwards borax' is s read upon the glowing surface and the a 0y poured out in a liquid state over thered glowing surfaces. After a further heating and further pouring out of the liquid alloy, a layer of'the'pure alloy is generallyv formed. Under certain conditions the pouring out must once more be repeated.

It isalso possible to (ii the iron surface to be coated into the mo ten alloy, so that by repeated dipping a coating of the alloy pro er may be obtained.

ally it inust-bementioned, that the several components of the alloy may be separately applied to the surface to be coated so that the previous comliination of the several substances is not necessary for obtaining the desired surface coating of the alloy.

ractical experience has shown that the alloy easily combines with iron so that there is no difiiculty, by any of the methods in coating iron vessels of any shape with a layer which resists the action of acids and the like.

Claim:

A method of coating vessels containing iron which comprises applying1 a flux to the vessel to be coated, heatmg t e vessel to a red heat in a reducing flame, applying an alloy comprising 10-11% of aluminum, 610% nickel, '25% oflead, .5% iron, and 81.5 73% copper to the heated surface and thereafter repeatedly heating the vessel and applying successive layers until the surface layer consistsof the pure alloy.

In testimony :whereof I have afiixed my signature,

MAX DREIFUSS. 

